JPH11237305A - Detecting apparatus for deviation of optical axis - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a detecting apparatus by which the deviation of an optical axis can be detected simply and with high accuracy even when the optical axis is adjusted for many hours, by providing a liquid mirror which uses the reflection on the surface of a liquid as the reference face for the adjustment of an optical system. SOLUTION: Since a reference flat 13, a beam expander 12 and a laser light source 14 are hard to arrange vertically, an optical path is bent vertically by an optical-path bending mirror 34. A Fizeau interferometer is constituted of a mercury mirror 33 which is constituted of mercury 31 and of a mercury reservoir 32. Due to the influence of the surface tension of the mercury 31, the peripheral part of the mercury mirror 33 cannot be used as a mirror surface. However, other parts of the mercury mirror 33 keep a flat face of extremely good accuracy. The liquid surface of the mercury mirror 33 is always kept perpendicularly to gravity as long as the direction of the gravity is not changed. As a result, it is possible to form a reference face whose flatness is high for many hours. Then, when the mercury mirror 33 is used instead of a reflecting mirror, the mercury mirror 33 which is surely reproducible and whose accuracy is high without using a firm fixation mechanism in order to support the mercury mirror 3 even when it comes into contact with the mercury mirror 33 mistakenly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for accurately detecting an optical axis shift by simple means.

[0002]

2. Description of the Related Art FIG. 8 shows an assembling procedure of an optical system 1, in which a first lens 3 is incorporated into a lens barrel 2, fixed by a lens holding jig 4, and then a second lens 5 is held. It is in a state where it is about to be fixed at the position shown by the broken line 7 using the tool 6. 8 is an imaginary axis where the center of curvature of the front surface and the center of curvature of the back surface of the first lens 3 exist (hereinafter, this axis is referred to as an optical axis), and 9 is the optical axis of the second lens. . If the optical axis 8 of the first lens and the optical axis 9 of the second lens are displaced, an aberration occurs, and satisfactory optical performance cannot be obtained. Install. Therefore, a device for detecting the displacement of the optical axes 8 and 9 of the lens is indispensable in assembling the lens. Hereinafter, a conventional optical axis deviation detecting device will be described.

FIG. 9 is a diagram showing a conventional apparatus for detecting axial displacement between lenses. A beam expander 12 including a collimator lens 10 and a spatial filter 11, a reference flat 13, a laser light source 14, and a reflecting mirror 1.
The optical axis shift of the afocal optical system 19 constituted by the objective lens 17 and the eyepiece 18 is measured by using the Fizeau interferometer 16 constituted by 5. In addition,
The lens barrel of the afocal optical system 19 is omitted.

When there is no afocal optical system 19, the reflected light partially reflected by the reference flat 13 and the reflected light of the reflecting mirror 15 interfere with each other, and an interference fringe 20 as shown in FIG. 10 is observed. If there is a poor adjustment (focus shift) in the lens interval of the afocal optical system 19, the shape of the interference fringe changes as indicated by 21 in FIG. In addition, since the axis shift causes astigmatism and the like, interference fringes as shown at 22 in FIG. 12 can be observed. As described above, the direction and amount of focus shift of the afocal optical system 19 and the direction and amount of axial shift can be known from the shape of the interference fringes.

FIG. 13 shows a conventional optical axis deviation detecting device using an autocollimator 23. The autocollimator 23 and the reflecting mirror 15 are installed so as to face each other, and the afocal optical system 19 is installed therebetween to detect an optical axis shift.
The autocollimator 23 is a device that measures an angular deviation from the return light reflected by the reflecting mirror 15 and returned to the autocollimator 23 again with reference to the light emitted by the autocollimator 23. As shown by the optical path 24 in FIG. 13, the angle of the return light to the autocollimator 23 is the same as the emission angle of the light emitted from the autocollimator 22. This state is a state in which the adjustment of the afocal optical system 19 has been completed.

FIG. 14 shows an optical path 24 passing through an afocal optical system 19 whose optical axis has not been adjusted. The optical axis 26 of the eyepiece 18 is shifted from the optical axis 25 of the objective lens 17. In such a case, the optical path 24
As shown in FIG. 7, the light reflected by the reflecting mirror 15 enters the autocollimator 23 at different angles. By measuring the difference in the angle with the autocollimator 23, the optical axis shift can be detected.

FIG. 15 shows another conventional optical axis deviation detecting device using laser light. This device is a laser light source 1
The laser beam 27 having a small luminous flux emitted from the laser beam 4 is detected as an optical axis shift of each lens which is arranged as if it were the optical axis of an optical system to be assembled. Hereinafter, it will be described that the optical axis deviation can be detected by this method.

FIG. 16 shows an optical path of light having a small light beam diameter (hereinafter, referred to as a light ray) incident on the single lens 28. The light beam 29 passing on the optical axis of the single lens 28 is not bent by the single lens 28, but the angle bent by the single lens 28 increases as the distance from the lens optical axis increases, as in the light beams 30a and 30b. If the reflecting mirror 15 is provided, it can be seen that only the light ray 29 passing through the optical axis of the single lens 28 has the same optical path as the reflected light and the incident light. As described above, the difference between the optical axis of the lens and the light beam can be determined by the difference in the optical path between the incident light and the reflected light. When assembling an optical system composed of a large number of lenses, it is possible to easily detect the deviation of the optical axis by performing the above operation each time a lens is added.

[0009]

In the optical axis deviation detecting apparatus described above, when the optical axis adjustment is required for a long time, the reflecting mirror serving as the reference plane changes at room temperature or the frame of the frame supporting the reflecting mirror is changed. There has been a problem in that the shape of the reflecting mirror changes due to deformation or the like, and aberration occurs, resulting in a detection error of an optical axis shift.

Further, when the position of the reflecting mirror is shifted due to an unexpected situation, it is necessary to restart the operation for detecting the optical axis shift from the beginning.

[0011]

An optical axis deviation detecting device according to a first aspect of the present invention includes a liquid mirror using reflection on the surface of a liquid as a reference plane for adjusting an optical system.

Further, the optical axis deviation detecting device according to the second invention is provided with a mirror which supports a conical body whose bottom surface is mirror-finished by a gimbal as a reference surface for optical system adjustment.

In the optical axis deviation detecting device according to the third invention, an interferometer is used as a means for measuring an adjustment deviation of the optical system, and a liquid mirror or a cone is supported by a gimbal on one reflecting mirror of the interferometer. It has a mirror.

The optical axis deviation detecting apparatus according to a fourth aspect of the present invention uses an autocollimator as a means for measuring an optical system adjustment deviation, and a mirror having a liquid mirror or a cone supported by a gimbal as a reference surface for optical system adjustment. It is provided with.

The optical axis deviation detecting apparatus according to the fifth invention uses a laser beam as a reference of the optical axis, and has a liquid mirror or a mirror supporting a cone with a gimbal as a reference plane for optical system adjustment. is there.

The optical axis deviation detecting device according to a sixth aspect of the present invention includes a light source in which a laser light source is mounted vertically on a flat plate.

The optical axis deviation detecting device according to a seventh aspect of the present invention includes a laser light source and a jig for adjusting an angle of a flat plate on which the light source is mounted.

An optical axis deviation detecting device according to an eighth aspect of the present invention is provided with a mirror provided with a mark and a gimbal supporting a cone whose bottom surface is mirror-finished.

An optical axis deviation detecting device according to a ninth aspect of the present invention includes a mirror provided with a mark at the center of the reflecting mirror and a gimbal supporting a cone whose bottom surface is mirror-finished.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 shows an optical axis deviation detecting apparatus according to Embodiment 1 of the present invention. In FIG. 1, it is the same as the conventional example of 11-14 and 17-18. Since it is difficult to arrange the reference flat 13, the beam expander 12, and the laser light source 14 vertically, the optical path is vertically bent by the optical path bending mirror 34. A Fizeau interferometer is composed of a mercury mirror 33 composed of mercury 31 and a mercury reservoir 32. The peripheral part cannot be used as a mirror surface due to the effect of the surface tension of the mercury 31, but the other parts maintain a flat surface with extremely high accuracy, and the liquid level is maintained unless there is a fluctuation in the direction of gravity. It is always kept perpendicular to gravity. Therefore, a reference plane with high flatness can be formed for a long time. Even if the configuration is almost the same as that of the conventional example, if a mercury mirror 33 is used instead of the reflecting mirror 15, a strong fixing mechanism is not used to support the mirror, and even if the mercury mirror 33 is inadvertently contacted, it is surely provided. A reproducible and highly accurate mirror is obtained. As a result, highly accurate optical axis deviation detection can be performed.

Embodiment 2 FIG. Figure 2 shows the autocollimator 2
3 is an optical axis shift detecting apparatus according to Embodiment 2 of the present invention using the optical axis 3; A mercury mirror 33 composed of mercury 31 and a mercury reservoir 32 is provided instead of the conventionally used reflecting mirror 15, and the optical axis deviation is measured by the autocollimator 22. As in the first embodiment, by using the mercury mirror 32, a stable and high-precision reflecting mirror can be obtained, so that high-accuracy optical axis deviation detection can be performed.

Embodiment 3 FIG. FIG. 3 shows an optical axis shift detecting device using a laser light source 14 according to a third embodiment of the present invention. The laser light 27 emitted from the laser light source 14 is regarded as the optical axis of the optical system to be assembled, and the optical axis of the lens 28 constituting the optical system is adjusted. Reflector 15 conventionally used
Instead, a mercury mirror 33 composed of a mercury 31 and a mercury reservoir 32 is provided. When the lens 28 is misaligned as indicated by the broken line, the light beam does not pass through the same optical path as shown in the conventional example, so that the optical axis misalignment can be detected based on this property. According to this apparatus, a stable and high-precision reflecting mirror can be obtained, and high-precision optical axis deviation detection is possible.

Embodiment 4 FIG. 4A shows a mirror used in place of the mercury mirror 33 in the optical axis deviation detecting device according to the fourth embodiment of the present invention. FIG. 4B is a side view of FIG. 4A as viewed in the direction of arrow A. In this embodiment, a quadrangular pyramid whose bottom 35 is mirror-finished is used. This mirror has a support structure described below so that it can rotate around a rotation axis shown at 37 in FIG. 4 and a rotation axis shown at 38 as c. Support rods 40a and 40b are provided at two diagonal locations 39a and 39b on the bottom side of the quadrangular pyramid 36, and bearings 42a and 42b are provided on the supporting ring 41 to reduce friction against rotation. Further, a support rod 44 is provided at a middle point 43a, 43b of the two support points 39a, 39b.
a and 44b, and are supported by bearings 46a and 46b attached to the support member 45.

When the quadrangular pyramid 36 is supported by the above-described structure, the bottom surface 35 of the quadrangular pyramid faces upward. The normal vector of the bottom surface 35 of the quadrangular pyramid is substantially parallel to the direction of gravity and always faces in a certain direction. Therefore, similarly to Embodiments 1 to 3, the bottom surface 35 of the quadrangular pyramid can be used as a stable reference plane,
The optical axis shift of the optical system can be detected with high accuracy.

A mark 47 is provided at the center as shown in FIG.
If the optical axis of the optical system is set near the mark, the bottom surface 35 of the quadrangular pyramid 36 supported by the gimbal can be used most effectively.

Embodiment 5 FIG. 6 shows an optical axis deviation detecting apparatus according to Embodiment 5 of the present invention. The laser light source 15 fixed by the laser fixing jig 48 includes angle adjusting knobs 49a and 49.
The angle adjustment with the circular flat plate 50 is enabled by b. As in the third embodiment, this apparatus detects an optical axis shift using the laser beam 27 as an opposition to the optical axis. Hereinafter, this usage method and functions will be described.

In FIG. 7, a circular flat plate 50 to which a laser light source 15, a laser fixing jig 48, and angle adjusting knobs 49a and 49b are attached is attached to a lens holding jig 6, and a reflecting mirror 15 is installed. Rotate the circular plate 50,
When observing the emission direction of the laser light 27, if the emission direction is not perpendicular to the circular plate 50, the emission direction of the laser light 27 changes according to the rotation of the circular plate 50. In this case, the emission direction of the laser beam 27 is changed by the angle adjustment knobs 49a and 49b, and adjustment is performed so that the emission direction does not change.

Next, by adjusting the direction including the lens barrel 1 so that the laser beam 27 is reflected by the reflecting mirror 15 and returns on the same optical path, the inclination of the lens barrel 1 with respect to the normal direction of the reflecting mirror 15 is adjusted. I do. Next, a lens is attached to the lens barrel 1 to detect an optical axis shift of the lens. The lens optical axis shift detecting method can be performed by the same method as in the third embodiment.

[0029]

According to the first aspect of the present invention, the reference of the optical axis can be easily obtained, and the direction reproducibility of the surface is good even when the reference surface is moved due to an unexpected situation. Also in the optical axis adjustment, a high-precision reference plane can be easily obtained, and as a result, high-precision optical axis deviation detection can be performed.

According to the second aspect of the present invention, by providing the mirror supported by the gimbal, a reference surface with good reproducibility can be obtained, and the optical axis deviation can be easily detected.

According to the third aspect of the present invention, the use of an interferometer in the optical axis deviation detecting device enables the axis deviation and the focus deviation to be measured with high accuracy. it can.

According to the fourth aspect of the present invention, the displacement of the optical axis can be easily detected by using the auto-collimator for the optical axis displacement detecting device.

According to the fifth aspect of the present invention, the apparatus can be inexpensively constructed by using a laser light source as the light source of the axis deviation measuring light.

According to the sixth aspect of the present invention, since the laser light source is mounted vertically to the flat plate, the adjustment can be performed by opposing the flat plate and the laser light source to detect the optical axis deviation of the lens and to adjust the mirror. The displacement between the tube and the lens can be detected.

Further, according to the seventh aspect, since the mounting angle between the laser light source and the flat plate can be adjusted, the accuracy of manufacturing the jig can be reduced.

According to the eighth aspect of the present invention, by providing a mark on the mirror supported by the gimbal, the optical axis deviation can be easily detected.

According to the ninth aspect of the present invention, the mark provided on the mirror supported by the gimbal is centered so that the mark coincides with the optical axis position of the optical system. The supported reflector can be used effectively.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of an optical axis deviation detecting device according to the present invention;

FIG. 2 is a diagram showing Embodiment 2 of an optical axis deviation detecting device according to the present invention.

FIG. 3 is a diagram showing a third embodiment of the optical axis deviation detecting device according to the present invention;

FIG. 4 is a diagram showing a fourth embodiment of the optical axis deviation detecting device according to the present invention;

FIG. 5 is a diagram showing a configuration of another optical axis deviation detecting device according to Embodiment 4 of the present invention.

FIG. 6 is a diagram showing a fifth embodiment of the optical axis deviation detecting device according to the present invention.

FIG. 7 is a diagram showing a method of adjusting a laser and a circular flat plate in an optical axis deviation detecting apparatus according to Embodiment 5 of the present invention.

FIG. 8 is a diagram showing a method of assembling the optical system.

FIG. 9 is a diagram showing a configuration of a conventional optical axis deviation detecting device using an interferometer.

FIG. 10 is a diagram showing interference fringes observed by a conventional optical axis deviation detecting device using an interferometer.

FIG. 11 is a diagram showing an interference image observed at the time of poor lens spacing adjustment in a conventional optical axis deviation detecting device using an interferometer.

FIG. 12 is a diagram showing interference fringes observed when an axis shift occurs in a conventional optical axis shift detecting apparatus using an interferometer.

FIG. 13 is a diagram showing a configuration of a conventional optical axis deviation detecting device using an autocollimator.

FIG. 14 is a diagram showing an optical path of a light beam passing through an afocal optical system whose optical axis has not been adjusted.

FIG. 15 is a diagram showing a configuration of a conventional optical axis deviation detecting device using a laser.

FIG. 16 is a diagram illustrating the adjustment principle of a conventional optical axis deviation detecting device using a laser.

[Explanation of symbols]

1 optical system during assembly, 2 lens barrel, 3 first lens, 4 first lens holding jig, 5 second lens,
6 holding jig for the second lens, 7 second lens mounting position, 8 optical axis of the first lens, 9 optical axis of the second lens, 10 collimator lens, 11 spatial filter, 12 beam expander, 13 reference flat, 14 laser light source, 15 reflector, 16 Fizeau interferometer, 17 objective lens, 18 eyepiece,
19 Afocal optical system, 20 Interference fringe when no afocal optical system is inserted, 21 Interference fringe when there is a focus shift, 22 Interference fringe when there is an axial shift, 23 Autocollimator, 24 Optical path, 25 Object Optical axis of lens, 26 Optical axis of eyepiece, 27 Laser light, 28 Single lens, 29 Ray passing through optical axis, 3
0 ray passing off the optical axis, 31 mercury, 32 mercury reservoir, 33 mercury mirror, 34 folding mirror, 35 pyramid bottom, 36 square pyramid, 37 rotation axis, 38 rotation axis, 39
Square pyramid support points, 40 support rods, 41 rings, 42
Bearing, 43 support point midpoint, 44 support point midpoint support rod, 45 support member, 46 bearing, 47
Mark, 48 Laser fixing jig, 49 Angle adjustment knob, 5
0 Round plate.

Claims (9)

[Claims] 1. An optical axis shift detecting apparatus for detecting an optical axis shift of a lens with respect to an optical axis of a test optical system in which a plurality of lenses are arranged at predetermined intervals on an optical axis. A light source for generating measurement light provided at one end of the optical axis of the system,
A liquid mirror that is provided at the other end of the test optical system and reflects the measurement light passing through the test optical system toward the light source and using reflection on the surface of the liquid, and reciprocates between the liquid mirror and the light source An optical axis deviation measuring device for measuring an optical axis deviation of the optical system to be measured from the measured measurement light. 2. An optical axis shift detecting device for detecting an optical axis shift of a lens with respect to an optical axis of a test optical system in which a plurality of lenses are arranged at predetermined intervals on an optical axis. A light source for generating measurement light provided at one end of the optical axis of the system,
A gimbal that reflects the measurement light passing through the test optical system provided at the other end of the test optical system in the direction of the light source and mirror-processes the bottom surface of the cone and the gimbal that always holds the bottom surface of the cone vertically upward. An optical axis shift detecting device, comprising: a configured reflecting mirror; and an optical axis shift measuring unit configured to measure an optical axis shift of an optical system to be measured from measurement light reciprocated between the reflecting mirror and the light source. 3. The optical axis deviation detecting device according to claim 1, further comprising an interferometer as the optical axis deviation measuring means. 4. The optical axis deviation detecting device according to claim 1, further comprising an autocollimator as the optical axis deviation measuring means. 5. The optical axis deviation detecting device according to claim 1, further comprising a laser light source and a means for measuring an optical path deviation of a laser beam emitted from the laser light source as a light source. 6. A laser light source as a light source, a flat plate used as a reference plane perpendicular to an optical axis, a mounting jig for mounting the laser light source vertically to the flat plate, and an optical path deviation measuring unit for a laser beam emitted from the laser light source. The optical axis deviation detecting device according to claim 5, wherein: 7. A jig for adjusting a mounting angle between a flat plate used as a reference plane perpendicular to an optical axis by attaching a laser light source and the laser light source.
The optical axis deviation detecting device as described in the above. 8. The optical axis deviation detecting device according to claim 2, wherein a mark is provided on the reflecting mirror. 9. The optical axis deviation detecting device according to claim 8, wherein a mark is provided at the center of the reflecting mirror.